Sample container holder

ABSTRACT

A sample container holder is provided for gripping a sample container which contains a sample. The sample container holder comprises a body having a bore for receiving a sample container. A flexible element is disposed within the bore. A fluid passage is operatively connected with the flexible element for supplying a fluid to the flexible element such that, when the sample container is received in the bore in the body of the sample container holder, the flexible element engages the sample container with a conforming, cushioning compression of sufficient magnitude to resist removal of the container from the bore.

REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. Ser. No. 08/086,744,filed Jul. 2, 1993, now U.S. Pat. No. 5,306,469, the disclosure of whichis specifically incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a container holder for automatedanalytic systems. More particularly, the invention relates to a holderfor gripping and holding sample containers as the containers aretransported, inverted to mix or agitate their contents or otherwisemoved.

BACKGROUND OF THE INVENTION

Holders now used in the field of automated clinical analysis may employmechanical grip devices for gripping sample containers after the holdersare positioned over the upper portions of the containers. In addition tooften being complex and hard to clean, some mechanical grippers haveother disadvantages. These grippers may not readily accommodate samplecontainers having different diameters or varying cap configurations.Furthermore, in the event of a power or other failure, a mechanicalgripper may lose its grip on the container. The containers may bedropped, thereby spilling their contents.

A further disadvantage may be present when a holder with a mechanicalgrip device is employed in a mixer or shaker device which inverts theholder and the containers in order to mix the contents of thecontainers. Since a mechanical gripper often grips the upper portion ofthe sample containers but not their caps, a cap may separate from acontainer during the inverting process thereby spilling the containercontents.

SUMMARY OF THE INVENTION

An object of an embodiment of the present invention is to provide asample container holder which is relatively easy to clean and is capableof handling sample containers having different diameters and/ordifferent cap configurations.

Another object of an embodiment of the invention is to provide a samplecontainer holder having a fail-safe mode of operation such that thesample containers are positively gripped in the event of a power orother failure.

Still another object of an embodiment of the invention is to provide asample container holder which grips both the sample containers and theircaps so that, upon inversion of the holder, the caps will not separatefrom the containers.

A sample container holder is provided for gripping a sample containerwhich contains a sample. The sample container holder comprises a bodyhaving a bore for receiving a sample container. A flexible element isdisposed within the bore. A fluid passage is operatively connected withthe flexible element for supplying a fluid to the flexible element suchthat, when the sample container is received in the bore in the body ofthe sample container holder, the flexible element engages the samplecontainer with a conforming, cushioning compression of sufficientmagnitude to resist removal of the container from the bore.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a prior art mixer device, modified toinclude a sample container holder comprising an embodiment of thepresent invention;

FIG. 2 is a perspective view of the holder of FIG. 1;

FIG. 3 is a top view of the holder cap;

FIG. 4 is a bottom view of the holder cap;

FIG. 5 is a top view of the holder body;

FIG. 6 is a sectional view of the holder body taken along the line 6--6of FIG. 5;

FIG. 7 is a sectional view of the holder body taken along the line 7--7of FIG. 6;

FIG. 8 is a bottom view of the holder body; and,

FIG. 9 is a sectional view of a part of the holder illustrating thegripper for one container and its cap.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

For the sake of clarity of understanding, embodiments of the presentinvention will be discussed in detail with respect to their employmentswith a container that holds a sample. However, it is to be noted thatthe embodiments of the invention can be utilized with containers holdingother things or with types of vessels different from those described andillustrated in the Figures. Additionally, for the sake of clarity, theembodiments of the invention are illustrated in the Figures associatedwith a plurality, specifically four, containers. It is to be rememberedthat the embodiments of the invention may be used with any number ofcontainers. Therefore, the gripper illustrated in FIG. 9 may be the onlygripper associated with the container holder. Alternatively, more thanone gripper may be associated with a single container holder. All ofthese permutations are possible without departing from the scope of thepresent invention.

FIG. 1 schematically illustrates a prior art mixer or shaker deviceincluding a sample container holder 18 constructed according to theteachings of the present invention. The mixer device has a head assembly10 comprising a reversible stepper motor 12, an L-shaped clamp 14, and avertically extending shaft 16. In the illustrated embodiment, the holder18 is mounted on the shaft 20 of the stepper motor 12 so that the holder18 may be rotated in substantially opposite directions through an angle,preferably measuring about 150°, as the motor 12 is energized.

The motor 12 is attached to clamp 14 by a plurality of fasteners 22. Anaperture 24 is provided in the clamp 14 so that the motor shaft 20 mayextend therethrough. The shaft 16 extends through an aperture 26 in aleg 14a of the clamp 14. The leg 14a is bifurcated from the aperture 26to the edge of the leg 14a. Fasteners 28 are provided for securing theleg 14a to the shaft 16.

The head assembly 10 is movable in a Z direction, as shown in FIG. 1, bya conventional mechanism (not shown) which may be controlled by acontroller 30 which may be microprocessor-based. The controller 30 alsomay control energization of stepper motor 12 to rotate the holder 18,and energization of a conventional conveyor mechanism (not shown) whichconveys container carriers 32 in an X direction, as shown in FIG. 1, toa position adjacent the holder 18. Each container carrier 32 has atleast one receptacle or recess 36 therein and supports one or morecontainers 34 having caps or closures 34a. The containers 34 may bepre-evacuated containers, test tubes or similar sample containers havingcaps or closures for preventing spillage of a sample contained therein.

In the illustrated embodiment, the head assembly 10 is moved to a raisedposition after which a carrier 32 is moved into position adjacent theholder 18. The head assembly 10 is then moved such that the caps 34a andportions of containers 34 enter the holder 18. The holder 18 is thenactuated to grip the containers 34 and the head assembly 10 is raiseduntil ends of the containers 34 are clear of the carrier 32. The steppermotor 12 is then actuated to rotate holder 18 and the containers 34through an arc, preferably measuring about 150 degrees, after which theholder 18 is rotated back through an arc, which may be the same as thefirst-mentioned arc, until the containers 34 are again in asubstantially vertical position. The arcuate rotation may be repeatedone or more times as dictated by the controller 30.

In an exemplary embodiment, the rotation of the holder 18 and container34, first in one direction and then another, can shake and mix thecontents of the containers 34. After the mixing is completed, the headassembly 10 is moved to replace the containers 34 in the carrier 32. Theholder 18 releases the containers 34 and the head assembly 10 is movedso that the holder 18 is offset from the containers 34. The conveyermechanism is then actuated to move the carrier 32 from a positionadjacent the holder 18 and to place another carrier 32 in its place.This completes one mixing cycle and the device is ready to repeat themixing cycle using a new group of containers 34.

For the sake of simplicity, FIG. 1 shows a carrier 32 having only onerow of container-receiving receptacles 36. However, carriers having morethan one row of receptacles may be used. In the latter case, thecontroller 30 preferably is programmed to index the conveyor mechanismwhich transports the carriers by the distance between centers ofadjacent rows of receptacles after each mixing cycle and another carrieris moved into position only after all the samples in a preceding carrierhave been mixed.

In an exemplary embodiment, the holder 18 utilizes fluid actuatedgrippers for gripping and holding the containers 32 as they are movedand/or shaken. As shown in FIG. 2, the holder 18 comprises a cap orcover 40 and a body 42. The cap 40 has at least one aperture 46extending through it. The apertures 46 are counterbored from one side asshown in FIG. 3. A corresponding number of apertures 48 (FIG. 5),preferably threaded, are provided in the surface 50 of body 42. The cap40 is secured to body 42 by fasteners (not shown) which extend throughapertures 46 and engage mating members, such as threads, in apertures48.

The cap 40 is provided with at least one bore 59 (FIG. 3) extending fromone side of the cap 40 to the opposing side. A metal insert 52 (FIG. 2)is placed and preferably press-fitted into bore 59. The insert 52 ispreferably internally threaded from both sides. At least one bore 54 isdrilled into one end of cap 40 and through insert 52. The shaft 20 ofstepper motor 12 is inserted into bore 54. Fasteners (not shown) areinserted into both ends of insert 52 and tightened against the shaft 20thereby securing cap 40 and body 42 to the shaft 20.

As shown in FIG. 4, the bottom surface 56 of cap 40 is provided with atleast one annular recess 58. The number of recesses 58 is preferablyequal to the number of containers 34 which may be concurrently held byholder 18. This number is four in the illustrated embodiment. Eachrecess 58 accommodates an O-ring 88 (FIG. 9) to provide a seal assubsequently described.

FIGS. 5-8 show details of the holder body 42. The body 42 is providedwith at least one bore 60, four bores 60 being shown in the Figures,extending through the body 42. Bores 60 are counter-bored from thesurface 62 thereby forming inwardly projecting ledges 64 near an end ofeach bore 60. From ledges 64, the body 42 is flared outwardly at anangle, preferably measuring about 30°, thereby forming truncatedgenerally cone-like surfaces 66. The flaring of the body 42 to formsurfaces 66 serves two purposes. First, the surfaces 66 guide thecontainers 34 toward bores 60 as the holder 18 is moved with respect tothe containers 34. Secondly, the surfaces 66 provide a wide mouth andthus a better angle for drilling a plurality of openings 68 in the sidewalls of bores 60.

As subsequently explained, the openings 68 form part of a fluid passagethrough which positive or negative pressures may be applied to theinterior of bores 60 to inflate or deflate bladders 82 (FIG. 9) disposedwithin the bores 60. The positive or negative pressures may be deliveredthrough the fluid passage in the form of an appropriately pressurizedfluid, such as air or other gas. An opening 68 is provided forinterconnecting each adjacent pair of bores 60. To complete the fluidpassage, a further opening 72 (FIG. 7) extends from one side of body 42to the opening 68 connecting two adjacent bores 60. The opening 72 ispreferably threaded and receives an elbow 74 (FIG. 1) having a flexiblehollow tube 76 connected thereto.

The cap 40 and body 42 may be made from any suitable polymeric material,such as plastic and the like. By way of example only, the cap 40 may bemade from a polymeric compound such as a substantially clear acrylicresin and the body 42 may be made of a polymer like white Delrin orwhite cast polyurethane.

FIG. 9 is a sectional view of a portion of the holder 18 showing one ofthe bores 60. Mounted within the bore 60 is a first tubular element 80and a second tubular element 82. Tubular element 80 is a rigid,preferably metal, cylinder having a plurality of bores 84 extendingthrough its side wall. The tubular element 82 comprises a flexible,preferably silicone rubber, tube or bladder. In an exemplary embodiment,the tubular element 82 is made of an elastomeric material havingsufficient elasticity such that at least a portion of the tubularelement 82 can conform to a profile or external configuration of thecontainer 34 and/or the cap 34a when the tubular element 82 sufficientlyengages the container 34 and/or the cap 34a. This promotes retention ofthe container 34 within the bore 60 and retention of the cap 34a on thecontainer 34.

In the illustrated embodiment, the flexible element 82 is longer thanthe rigid element 80 so that its ends 82a may be radially stretched andfolded back over the outer surface 80a of the rigid element. The outerdiameter of element 82 is preferably smaller than the inner diameter ofelement 80 so that when ends 82a are folded back a preferably air-tight,annular region or chamber 86 is formed between the elements 80 and 82.In a practical embodiment the diameter of the flexible element 82,before it is mounted on element 80, may be about 5/8" and the diameterof element 80 may be about 7/8" although these dimensions may be changedto accommodate containers 34 of different sizes. At least one bore 84 inelement 80 serves as a mechanism for allowing fluid movement into andout of the region 86. Preferably, at least four bores 84 are spacedaround the periphery of element 84.

After the tubular elements 80 and 82 have been assembled, they areinserted into bore 60 from the top of body 42, as viewed in the Figures,after which the O-ring 88 is positioned on the body 42 and the cap 40 issecured to the body 42.

In the illustrated embodiment, the inner diameter of the flexibleelement 82 is chosen such that when the element 82 is folded back overthe rigid element 80, the element 82 forms a throat region T whoselargest diameter is preferably smaller than the diameter of the cap 34aand container 34 it is intended to grip. The diameter of the rigidelement 80 is preferably smaller than the diameter of bore 60, butlarger than the throat region T bounded by ledge 64, so that the ledge64 supports elements 80 and 82 within bore 60. When the cap 40 is placedon body 42, the O-ring 88 presses against the tubular element 82 in theannular region 82b where it folds over an end of the rigid element 80and this in turn presses an annular region 82c at another end of element82 against ledge 64. An annular region or chamber 90, which ispreferably hermetically sealed, is thus formed between the wall boundingbore 60 and the outer surface 80a of rigid element 80. The chamber 90permits a fluid pressure present at one of the openings 68 to becommunicated to the region 86 through all of the openings 84. Thechamber 90 also permits a fluid pressure at a first opening 68a to becommunicated to an adjacent chamber 90' through a second opening 68b.

During use of the sample container holder 18, positive and negativepressures are selectively applied to the chamber 86 where "positive" and"negative" are defined relative to the pressure of the ambientenvironment in which the holder 18 is being operated.

To provide the positive and negative pressures, the opening 72 (FIG. 7)is connected via flexible tubing 76 (FIG. 1) and two electricallycontrolled valves 92 and 94 to a source 96 of negative pressure and asource 98 of positive pressure. Pneumatic pressures are preferredalthough hydraulic pressures may be used. Thus, the pressurized fluidmay also be a liquid. Controller 30 selectively produces output signalsto open either valve 92 or 94, thereby applying a negative or a positivepressure via tube 76 to opening 72. From opening 72, the pressure isdistributed via openings 68, regions 90 and bores 84 to the chambers 86.

As previously stated, in the preferred embodiment, the flexible element82 is chosen to have, at ambient pressure in chamber 86, an internaldiameter which is less than the diameter of a container 34 which is tobe retained by the holder 18. The internal diameter of rigid element 80is chosen such that when a vacuum or negative pressure is applied tochamber 86 to draw the flexible element 82 outwardly toward the internalsurface of the rigid element 80, a sample container 34 and its cap 34amay move into the interior of the flexible element 82. The openingbounded by ledge 64 should preferably have a diameter larger than thatof a sample container 34 and its cap 34a.

Referring now to FIGS. 1 and 9, the holder 18 is operated as follows.After a carrier 32 holding sample containers 34 is positioned adjacentholder 18, the controller 30 actuates valve 92 so that a negativepressure is applied via tube 76, bore 72 (FIG. 7), openings 68, regions90 (FIG. 9) and bores 84 to chambers 86. The negative pressure inchambers 86 draws the flexible elements 82 toward the interior surfacesof rigid elements 80.

Next, controller 30 energizes the mechanism to move the mixer assembly10. As the assembly 10 is moved, the caps 34a and upper portions ofsample containers 34 are directed toward the interiors of the flexibleelement 82 by the sloping surfaces 66. Controller 30 then terminates thesignal to valve 92 and energizes valve 94 so that a positive pressure isapplied to the chambers 86. This pressure forces the flexible elements82 away from the internal surfaces of rigid elements 80. As they moveinwardly, the elements 82, because they are flexible, engage both thecaps 34a and upper portions of the sample containers 34. The elements 82engage the containers 34 and the caps 34a with a cushioned, conformingcompression generated by pneumatic forces induced by the pressures. Thecushioning, conforming compression also permits the holder 18 to receiveand retain various containers 34 having variously different externalconfigurations or profiles. The flexibility of the elements 82 combinedwith the pneumatic forces allows the elements 82 to assume aconfiguration which complements, mirrors or mates with the externalconfiguration of the containers 34 and the caps 34a. This also reducesthe probability that the caps 34a might separate from the containers 34during the lifting and shaking operations which follow.

The controller 30 next energizes the mechanism to move the holder 18 andthe sample containers 34 until the sample containers 34 are free of thecarrier 32. The controller 30 then energizes stepper motor 12 to shakethe containers 34 by rotating them back and forth through an arc asdescribed above. After the containers 34 have been shaken, controller 30energizes the mechanism for moving the mixer assembly 10. As theassembly 10 is moved, portions of sample containers 34 are againreceived into the receptacles 36 in carrier 32.

The controller 30 now deenergizes valve 94 and energizes valve 92 toagain apply a negative pressure to the chambers 86. This draws theflexible elements 82 away from the containers 34 and the containers 34move into the carrier 32. This movement may be gravity assisted.Alternatively, an ejector of sorts may be provided. With valve 92 stillenergized, the controller 30 energizes the mechanism for moving themixer assembly 10. As the holder 18 is moved, the flexible elements 82move relative to the sample containers 34. This movement is relativelyfree because the pneumatic forces have been relaxed. The mixing cycle iscomplete once the holder 18 has been sufficiently offset from thecontainers 34. Once the holder 18 is offset from the containers 34sufficiently, a new container carrier 32 may be moved into positionadjacent holder 18.

The embodiments of the present invention provide distinct advantagesover the prior art. The holder 18 operates in a fail-safe mode which canreduce the chances of dropping a sample container 34 in the event of apower loss or other failures. Since the internal diameter of flexibleelements 82 is less than the diameter of the sample containers 34 whenambient pressure is present in chambers 86, the elements 82 will stillgrip the containers 34 even when positive pressure is lost because of apower or other component failure. The holder 18 will retain a container34 as long as the pneumatic forces generating the cushioning compressionon the container 34 and the cap 34a are of sufficient magnitude toresist a force directed to remove the container 34 from the holder 18,or, more precisely, from the bore 60 in the holder 18. As long as thecushioning compression applied to the container 34 or the cap 34a, orboth is of the sufficient magnitude, the container 34 will remain withthe holder 18.

Because gripping is accomplished by moving flexible elements 82 with apneumatic pressure, the holder 18 is able to grip containers 34 andtheir caps 34a even though the diameters of the containers 34 and thedesigns of their caps 34a may vary. This is a direct benefit of theconforming cushioning compression applied to the container 34 and thecap 34a by flexible elements 82.

From the foregoing description it is seen that the embodiments of thepresent invention provide a sample container holder which is simple inits construction, is able to accommodate sample containers of varioussizes, reduces the chances of separating containers from their caps, andreduces the chance of dropping containers in the event of a power lossor other failure.

While preferred embodiments of the invention have been described inspecific detail it will be understood that various modifications andsubstitutions may be made in the described embodiments without departingfrom the spirit and scope of the appended claims. Furthermore, althoughthe sample container holder has been described in the environment of amixer device, it should be understood that the holder may find generalutility as a transfer holder for transferring sample containers fromcarriers to analytical devices, from one stage to another of amulti-stage analytical device, etc.

I claim:
 1. A sample container holder for holding at least onecontainer, said holder comprising:(a) a body having at least one bore inwhich a container is received; (b) a cap mounted on said body coveringsaid container and bore; (c) first and second tubular elements ofdifferent inner and outer diameters disposed within said bore, saidfirst tubular element being rigid and having an inner diameter largerthan the outer diameter of said second tubular element, said secondtubular element being flexible and disposed within the first tubularelement with first and second ends of the second tubular element beingfolded back over first and second ends of the first tubular element soas to form a hermetically sealed chamber between said first and secondtubular elements; and said first tubular element and said body havingopenings therein comprising a fluid passage through which a negative ora positive pressure may be applied to said chamber to increase ordecrease, respectively, the inner diameter of said second tubularelement whereby a container may be received into a region bounded bysaid second tubular element when a negative pressure is applied, saidcontainer being gripped by said second tubular element when a positivepressure is applied.
 2. A sample container holder as claimed in claim 1wherein the inner diameter of the second tubular element is smaller thanthe outer diameter of the container to be received therein whereby acontainer is held by said second tubular element when said chamber is atambient pressure.
 3. A sample container holder as claimed in claim 1wherein said body has a ledge disposed about said bore at a first endthereof, said second tubular element, where it folds over the first endof the first tubular element, abutting said ledge, and an O-ringdisposed between said first and second tubular elements and said cappressing said O-ring against said second tubular element where it foldsover the second end of the first tubular element, whereby said body andsaid first tubular element bound an hermetically sealed passagecommunicating with the openings in said body and said first tubularelement.
 4. A sample container holder as claimed in claim 3 wherein saidbody and said cap have substantially flat mating surfaces and said caphas an annular recess facing said body for locating said O-ring.
 5. Asample container holder as claimed in claim 3 wherein said body forms asurface sloping downwardly and outwardly of said bore, said surfacedirecting a container being received toward the region bounded by saidsecond tubular element.